1826.]' .Scientific Notices— Chemistry. 2S3 



of arsenic. In order to do this, take a piece about three inches 

 long, of an ordinary barometer tube, and having drawn out one 

 «nd of it into a much narrower tube close the end. Let some 

 of the arsenic found in the body be now put in at the open or 

 laro'er end, so that it may fall down to the bottom. Any quantity 

 of this arsenic of sufficient volume to be taken from the body 

 •will suffice for this purpose. The arsenic being at the bottom of 

 the small part of the tube, a little charcoal is let fall upon it, after 

 it has been freed from all moisture by bringing it to a red heat with 

 the blowpipe. The charcoal is then heated in the tube at the flame 

 of a spirit-lamp, the point where the arsenic lies being held out of 

 the flame. When the charcoal is very red, the point containing the 

 arsenic is drawn into the flame. The arsenic is then instantly 

 volatilized, and passing into vapour by the red charcoal, it is 

 reduced, and reappears on the other side of the flame in a metallic 

 state. The flame is then brought slowly towards the metallic 

 sublimate, which is thus concentrated into a smaller space in the 

 small tuW~; and then presents a small metallic ring shining 

 like polished steel.* We have now only to verify, by its smell, 

 that the metallic sublimate is arsenic. For this purpose, cut 

 the small tube with a file a little above the sublimate, and having 

 heated the place where it lies, put the nose above it at a small 

 distance, and the particular odour of the metal will be imme- 

 diately perceived. 



In the case where the solid arsenic cannot be found, we must 

 collect as much as possible of the contents of the stomach and 

 the intestines, or even cut the stomach in pieces, and mix it 

 ■with its contents. The whole is then to be digested with a 

 solution of hydrate of potash. Hydrochloric acid is then added 

 in excess. The whole is filtered, and, if the liquid is too much 

 diluted, it is concentrated by evaporation. A current of sulphur- 

 etted hydrogen is then passed through it, which precipitates the 

 arsenic in the form of the yellow sulphuret. If the quantity of 

 arsenic is very small, the liquid will become yellow without giv- 

 ing a precipitate. It must then be evaporated, and in proportion 

 as the hydrochloric acid becomes more concentrated, the sul- 

 phuret of arsenic will begin to be deposited. It is then filtered. 

 If the sulphuret remaining on the filter is in too small a quantity 

 to be taken from the paper, add some drops of caustic ammonia, 

 which will dissolve it. Then put the liquid which passes the 

 filter into a watch-glass, and evaporate it. The ammonia will 

 be volatilized, and will leave as a residue the sulphuret of 

 arsenic. If it shall still be difficult to collect the sulphuret, we 

 must put into the watch-glass a little pulverized nitrate of 

 potash, and, with the finger, mix the sulphuret with the nitrate 



• H#d the experiment been made in the wide part of the tube, the icsult would 

 scarcely have beea vifiibk with a small quantity of aiseoic* 



